Abstract:
We study the implication problem for the combined class of functional and full
hierarchical dependencies in the presence of SQL's NOT NULL constraints. Two
different notions of implication are addressed: one where a dependency is implied
by the given set of dependencies plus the underlying schema, and one where a
dependency is implied by the given set of dependencies alone. We establish axiomatizations
for both notions of implication, and reveal deep relationships between
them.
